The Federal Trade Commission is considering proposing a do-not-track mechanism that would allow consumers to easily opt out of all online behavioral advertising. But the agency lacks the authority to mandate do-not-track.

Yes, the FTC can certainly say it thinks that Web companies should figure out a way to implement a universal do-not-track program, but can't do much more absent new legislation. And a do-not-track registry wouldn't stop marketers from sending online ads to people. Instead, it would prevent marketers from trailing people online and delivering ads based on users' Web history. What's more, any ad network that belongs to the Network Advertising Initiative already is (or should be) honoring a do-not-target mechanism -- the NAI opt-out cookie that allows people to opt out of behavioral advertising. Of course, the NAI program has a few drawbacks. One is that not every company participates. Another is that consumers often delete their cookies -- including their opt-out cookies. Yet another drawback, explains Jim Brock at Privacy Choice, is that companies who participate in the NAI program promise only that they won't send consumers targeted ads, not that they won't track users. Still, in principle, the NAI already offers something similar to what the FTC is touting, but on a smaller scale. Expanding that program might mean that more companies are honoring consumers' privacy preferences, but wouldn't mark a departure from existing self-regulatory principles.